US2624565A - Scrap melting - Google Patents

Description

Jan. 6, 1953 w. w. KOMPART SCRAP MELTING Filed June. 24, 1949 INVENTOR. WALTER W. KOMPART Patented Jan. 6, 1953 SCRAP MELTING Walter W. Kompart, Steubenville, Ohio, assignor to National Steel Corporation, a corporation of Delaware Application June 24, 1949, Serial No. 101,227

4 Claims.

This invention relates to an improved apparatus for melting pieces of metal and is primarily concerned with the melting of ferrous metal scrap, such as iron and steel scrap, and particularly scrap that is in relatively small pieces.

' In the production of steel in metallurgical furnaces-f or example, the open hearth furnacea relatively large quantity of cold ferrous metal scrap is charged into th furnace and then heated, ultimately, to melt down the scrap. After the scrap has been heated and either partially or completely melted, molten pig iron is charged into the open hearth, and, after suitable treatment, steel is produced containing the proper amount of carbon and other elements and having the desired characteristics. Charging such a large quantity of light solid scrap into the open hearth furnace requires considerable time, as does the heating and melting of the scrap. This in turn reduces the number of heats per furnace for a given period and reduces the number of tons of steel produced per day per furnace. The time required for heating scrap is increased when the scrap is relatively small or light. This type of scrap is cheaper, and it would be economical to use such scrap if the charging time could be greatly reduced.

More recently, it has been proposed that oxygen or oxygen-enriched air be used to burn the fuel for heating open hearth furnaces to increase the output of tons of steel per hour per furnace and thereby produce more steel per day with the same open hearth equipment. When oxygen is used,

metal into the furnace. These attempts have had various drawbacks, and, insofar as is known to me, the melting of steel and iron scrap prior to charging it into the open hearth is not being practiced by any steel producer.

Accordingly, it is an object of the present invention to provide an improved apparatus for pro-melting scrap before it is charged into a metallurgical furnace that will [be emcient and practical.

Another object of the present invention is to provide an improved apparatus for melting scrap that will rapidly and efliciently handle and melt down large quantities of relatively light-weight scrap. I

Another object of the present invention is to provide an improved apparatus for the melting 'of scrap that is so constructed that the hot gases more readily flow through the scrap and more efliciently heat and melt the scrap.

These and other objects and the advantages of the present invention will become apparent when considering the following description, taken with the accompanying drawing which is a diagrammatic, longitudinal sectional view of scrap melting apparatus embodying the principles of the present invention.

The present invention will be described in connection with the melting of steel scrap, but other ferrous metal scrap, such as iron scrap, may be melted in the same manner. In addition, for the sake of clarity, it will be considered that the molten scrap metal is charged into an open hearth furnace, it being understood that the molten metal may the charged into other metallurgical furnaces--f0r example, a Bessemer converter.

Referring to the drawing, the scrap melting apparatus includes an inclined furnace ID, a hopper or receiver l I and charging means I 2 for feeding the scrap metal from the hopper ll into the furnace I0. The receiver ll includes a substantially circular wall l3 enlarged to define a receiving chamber Id. The wall 13 defines a flue l5 at the upper end of chambe I4.

The furnace It includes an outer metal shell [6 lined with refractory material l! and supported on supports [8. The lining defines an inclined melting chamber It. An outlet 20 for the molten metal is provided at the lower end of the furnace. An elongated wall 23 extends into the furnace l0 and defines an elongated feed passage 24 terminating in an outlet 25. The elongated feed passage 24 includes an inlet portion 21 of uniform diamete throughout its length and an outlet portion 28 extending from the inlet passage portion 21 to an outlet 25. The walls of outlet or discharge passage 28 diverge outwardly toward the outlet 25, and the passage is substantially frusto-conical in shape, with the smaller end being the inlet end and the larger end being the outlet end at 25. The portion of the wall defining passage 21 contains an opening in the side which is also the outlet opening of a passage that communicates with the receiving chamber I 4 so that scrap is discharged by gravity from the upper hopper l4 through the passage 29 into the lower inlet passage 21. A piston 3! is mounted in feed passage 24 for movement through passage 2! and is connected through a rod 32 to suitable poweractuating means, such as a hydraulic cylinder 33;

for moving the piston through a feed stroke of predetermined length. The length of this feed stroke is at least as long as passage 21. The piston is shown in the drawing as being in the withdrawn position. The inlet passage 21, which is a portion of passage 24, extends from the forward end 34 of piston 3| to the inlet end of outlet passage 28. Passage 24 and piston 3| are of the same size. Preferably, the piston 3| is at least as long as the passage 2'! and is at least as long as the feed stroke. wardly through a feed stroke, the forward end of piston 3| moves at least all the way through passage 21 to the inlet of passage 28 and, if. the stroke is longer than passage 21, the piston will extend into passage 28 a shortdista-nce. Asthe piston is as long as the stroke, the piston 3| extends rearwardly far enough to cover the inlet 29 from chamber I4 50 that scrap cannot fall into passage 24 in back of the piston which would interfere with the return stroke. As the ,length of the piston stroke is at least as long as passage 21, all scrap initially in passage 21 at the start.

of the feed stroke is pushed into the passage28 and no scrap compressed by piston 3| on its feed stroke is left in passage 21.

A burner 35-is mounted in furnace i8 so as. to direct a flame 35 against the forward face of the pile of scrap inthe furnace. The burner 3545 connected to a suitable source of fuel (not shown) Oil or gas may be used as the fuel. The hot gaseous products of combustion flow through, the scrap and out stack l to preheat the scrap. A water-cooled jacket 3! encircles the wall of outlet passage28 to, cool the wall. Jacket 31' is connected through an inlet pipe 33 to a source'of cooling water (not shown) and is connected through an outlet pipe 39 to a sewer or other place of disposal.

In describing the operation of the scrap melting apparatus which is continuous, it will be assumed that the apparatus is initially in the condition shown in the drawing, with scrap in chamber l9, burner 35 on, and piston 3| in the return position. Scrap is charged by means of a buggy 49 or other means through a door 4| in the sideof hopper into the chamber 4. The scrap in chamber l4 falls through passage 29 into passage 27 and completely or partially fills passage 21. When it is desirable to feed more scrap into the melting chamber l9, the piston 3| is moved by motor 33 through passage 22' and through a stroke of predetermined length. Forwardmovement of piston 3| compresses and moves forwardly the scrap in passage 21 which in turn moves scrap in passage 28 forwardly through outlet 25 into chamber I9. As the stroke is as long as or longer than passage 2?, the feed stroke moves all of the scrap out of passage 2'! into pas? sage 28 where the compressed scrap can expand so that the hot gaseous products of combustion can more readily flow through the scrap. On the return stroke no pancake of compressed scrap is left in passage 2! to clog the passage as would be the case if the feed stroke were shorter than passage 21. When piston 3| moves forward, it closes inlet 29 and as the piston is as long as the stroke, the piston maintains the inlet 29 closed until the return stroke when inlet 29 i opened scrap again falls into passage 21. The piston 3| is operated intermittently to supply scrap to the furnace. The burner 35 operates continu: ously to melt the scrap. The molten scrap-collects in the bottom of chamber l9, flows out outlet 20- into arreceiver or ladle-.42 whichis used-to When the piston 3| is movedfor" v transport the molten scrap metal to the open hearth furnace.

As previously pointed out, the piston 3| on the feed stroke closes inlet 29 so that the gaseous products of combustion from the melting furnace cannot flow out through passage 29. Preferably, a bypass conduit 42 communicating with chamber I9 and flue l5 throughhopper chamber 4 is provided for bypassing the gases when passage 29 is closed. A valve 43 is interposed in conduit 42. Means for actuating the valve, such as a solenoid 44, is connected to the valve 43 and through wires 46 to a suitable control means 41 for energizing the solenoid and opening the valve 43 when piston 3| closes passage 29. The control means. may be a normally open switch mounted on hydraulic cylinder 33 and operable to the closed position by the inner end of piston rod 32 upon movement of the piston 3| outwardly far enough to close passage 29. With the switch closed the circuit to solenoid 44 through-Wires 46 is closed and the solenoid is energized to open valve 43. With valve 43 in the normal,-closed position, the gases flow through the scrap, but when valve 43 is open, the gases flow through the conduit 42 and out flue IS. The control means for controlling energization of solenoid 44 may be. of

any suitable type or may be connected to the means for actuating piston 3| so as automatically to open valve 43 when piston 3| ismoved forwardly through a feed stroke.

Whenever scrap metal is needed for the open hearth, molten ferrous metal scrap can be quickly poured into the furnace. Charging moltenmetal requires only a brief period, whereas hours are required to charge and heat scrap metal into an open hearth furnace. The present apparatus reduces the time required per heat and thereby increases production, and this apparatus quickly melts the scrap without clogging so that molten scrap is readily available. The scrap is in a relatively loose condition so that the hot gaseous products of combustion readily flow the scrap to preheat it which in turn reduces fuel costs.

I claim:

1. In apparatus for melting pieces of ferrous metal scrap, a melting furnace defining amelting chamber, means for charging scrap into the melting chamber including an elongated feed passage having a piston mounted therein, said feed passage including an inlet portionof the same uniform-size as the'piston extending forwardly from the piston. the inlet portion having an-inlet opening inthe side, and an outlet portionextending from theinlet portion to an outlet communicating with the meltingchamber. said outlet portion having sides diverging outwardly toward the outlet, power actuated means for moving the piston forwardly in the feed passage .through a feed stroke of predetermined length to push scrap in the inlet portion into the outlet portion, the feed stroke being at least as long as the inlet passage portion whereby all scrap in the inlet portion is pushed out into the outlet portion on each feed stroke, and said piston being at least as longas said stroke where-. by the piston maintains the inlet opening closed when in the forward position, flue means communicating with the elongated feed passage whereby gaseous products flow from the melt ing. chamber-through the feed passage and out the hue means, and by-pass means between the melting chamber and theflue means-operable upon the piston closing communication between.

the melting chamber and the flue means through the elongated feed passage.

2. In apparatus for melting pieces of ferrous metal scrap, a melting furnace defining a melting chamber, means for charging scrap into the melting chamber including an elongated feed passage having a piston mounted therein, said. feed passage including an inlet portion of the same uniform size as the piston extending forwardly from the piston, the inlet portion having an inlet opening in the side, and an outlet portion extending from the inlet portion to an outlet communicating with the melting chamber, said outlet portion having sides diverging outwardly toward the outlet, burner means for heating the scrap metal in the furnace chamber, hopper means defining a receiving chamber for the scrap, a passage between said inlet opening and said receiving chamber for feeding scrap through the inlet opening into the inlet portion of the feed passage, power actuated means for moving the piston forwardly in the feed passage through a feed stroke of predetermined length to push scrap in the inlet portion into the outlet portion,

the feed stroke being at least as long as the iii inlet passage portion whereby all scrap in the inlet portion is pushed out into the outlet portion on each feed stroke, and said piston being at least as long as said stroke whereby the piston maintains the inlet opening closed when in the forward position, the flue means communicating with the receiving chamber whereby gaseous products flow from the melting chamber through the feed passage and the receiving chamber and out the flue means, and by-pass means between the melting chamber and the flue means operable upon the piston closing communication between the melting chamber and the flue means through the feed passage and the receiving chamber.

3. In apparatus for melting pieces of ferrous metal scrap, a melting furnace defining a melting chamber, means for charging scrap into the melting chamber including an elongated feed passage having a piston mounted therein, said feed passage including an inlet portion of the same uniform size as the piston extending forwardly from the piston, the inlet portion having an inlet opening in the side, and an outlet portion extending from the inlet portion to an outlet communicating with the melting chamber, said outlet portion having sides diverging outwardly toward the outlet, burner means for heating the scrap metal in the furnace chamber, hopper means defining receiving chamber for the scrap, a passage between said inlet opening and said receiving chamber for feeding scrap through the inlet opening into the inlet portion of the feed passage, power actuated means for moving the piston forwardly in the feed passage through a feed stroke of predetermined length to push scrap in the inlet portion into the outlet portion, the feed stroke being at least as long as the inlet passage portion whereby all scrap in the inlet portion is pushed out into the outlet portion on each feed stroke, and said piston being at least as long as said stroke whereby the piston maintains the inlet opening closed when in the forward position, an outlet flue communicating with the receiving chamber, a bypass conduit communicating with the melting chamber and the flue, a normally closed valve in the conduit, and control means for opening the valve upon forward movement of the piston.

4. In apparatus for melting pieces of ferrous metal scrap, a melting furnace defining a melting chamber, means for charging scrap into the melting chamber including an elongated feed passage having a piston mounted therein, said feed passage including an inlet portion of the same uniform size as the piston extending forwardly from the piston, the inlet portion having an inlet opening in the side, and an outlet portion extending from the inlet portion to an out let communicating with the melting chamber, said outlet portion having sides diverging outwardly toward the outlet, burner means for heating the scrap metal in the furnace chamber, hopper means defining a receiving chamber for the scrap, a passage between said inlet opening and said receiving chamber for feeding scrap through the inlet opening into the inlet portion of the feed passage, flue means communicating with said receiving chamber whereby the gaseous products of combustion from the burner flow from the melting chamber, through the feed passage and the receiving chamber and out the flue means, power actuated means for moving the piston forwardly in the feed passage through a feed stroke of predetermined length to push scrap in the inlet portion into the outlet portion, the feed stroke being at least as long as the inlet passage portion whereby all scrap in the inlet portion is pushed out into the outlet portion on each feed stroke, and said piston being at least as long as said stroke whereby the piston maintains the inlet opening closed when in the forward position, and by-pass means between the melting chamber and the flue means operable upon the piston closing communication between the melting chamber and the flue means through the feed passage and the receiving chamber.

WALTER W. KOMPART.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 4,527 Fales May 16, 1846 405,134 Walsh, Jr June 11, 1889 473,741 Hansen Apr. 26, 1892 1,024,623 Dougherty Apr. 30, 1912 1,434,395 Meinersmann Nov. '7, 1922 1,739,278 Baily Dec. 10, 1929 1,904,781 Crawford Apr. 18, 933 2,068,448 Cox Jan. 19, 1937 2,264,740 Brown Dec. 2, 1941 FOREIGN PATENTS Number Country Date 8,759 Great Britain of 1890

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